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The above quoted article has been criticised for the author's selection of data sources which distort the conclusions, but the basic point is that wind farms today MUST always be a supplement to the base load grid. The wind can fail to blow for long periods but the power demand continues so you end up investing in a base load infrastructure (spinning reserve) that costs virtually the same as if there were no wind farms.
Despite the massive investment in wind turbine technology around the world, doubts remain. The main problem with increasing the proportion of wind power is meeting the base load demand, something wind power will not be capable of until much cheaper energy storage technology than exists today is developed. Sure, some countries with hydroelectric schemes may be able to pump water back up into reservoirs but this is hardly an efficient end-to end technology.
Until a cost-effective energy storage technology is developed, wind power will remain an option that can only increase electricity infrastructure costs.